We went recently and Miss 4 was beside herself. Check out the specials as we got some amazing tickets that had repeat entry to Dreamworld/Wet water world for the whole month of June! There were heaps of rides for the little kids here - really good Wiggles section for the toddlers and some great preschoolers stuff also. My kids are obsessed with Spongebob after seeing the stage show. They also loved seeing the White Tigers too. The kids loved these parks - there is a kids section called Wiggle Bay in the water park whick has great slides etc for the littlies - also the bigger kids would be happy there in the slides etc. It was great fun and the highlight of our trip. We also went to Seaworld which was great also and slightly different - our kids were too little for the rides but had a great time wandering around. The bigger kids would love some of the rides there lots of splashes and thrills!
The food was a big dissappontment as it was quite exxy and not much value out of the healthier options (but I guess that is no surprise really). Dreamworld was slightly cheaper and seemed better value. We ended up putting stuff in the pram etc and no one actually checked it out.
I would check out a few websites and even email the parks to check out the entry offers for the time period you are there.
We did have a break between parks as the kids were exhausted!!!! It was heaps of fun and we are hoping to go again when I can save my pennies. Perfect holiday for the kids - which means perfect for the big kids!!!!
ETA - we went to Dreamworld twice and I think we could have easily gone back a third time. First day we did the rides, shows and scoped out the water park - second day we caught up on things we missed and then spent half a day in the water park.